Engineering

Engineering

Unit configurations

Download unit configurations sheet

Coil selections

Our engineering office provides ratings on all coil selections using certified computer software.

The programs provide numerous options, from the most efficient to selections having the lowest air or water pressure drops.

Full print-outs are freely available upon request.

Computer programs are used for the following types of media:

  • chilled water
  • hot water
  • heat reclaim
  • steam coils
  • direct expansion
  • condenser.

Fan selections

All fan selections are carried out on a system by system basis.

A standard range of fans exist for each unit, as indicated in the attached data. Specific selections are always made. Upon determining airffow against static pressure, our engineering office provides numerous fan selections taking into consideration efficiency, acoustic requirements and space limitations. Fan curves with performance schedules are all certified and freely available upon request.

Maintenance data - Finned coils

The primary maintenance considerations for finned air handling and cooling coils for cleanliness of the heat transfer surface and freedom from corrosion and leaking.

In the best of filtered systems, coil fins and tubes can become clogged with dust, fluff, lint, etcetera, which may become the source of external corrosion in addition to reducing heat transfer efficiency.

The frequency of cleaning will depend upon the cleanliness of the air flowing through the coil. If used for heating or cooling outdoor air, where the intake is close to street level in areas with a high degree of air pollution, more frequent inspections will be required than they would where the intake is high and air pollution light.

Therefore cleaning should be carried out at least once a year and more often, if the coils are subject to heavier dust loading conditions.

Cleaning may be accomplished in some cases by hand-brushing, but for multiple row coils, a compressed air jet is the best means. When necessary, more thorough cleaning can be obtained by means of a steam gun, followed by compressed air for drying off the coil.

Internal steam cleaning may be necessary in cases where viscous oil type air filters precede the coil and oil mist is carried on to the coil fins.

For severe cases, the coil must be removed from the installation and sprayed with a mild alkali cleaning solution, followed by very thorough steam rinsing and compressed air drying.

It is essential when cleaning the coil that adequate precautions are taken to collect any dust or moisture blown off the coils from passing into the air conditioning duct system.

The coil casing should also be inspected for rust and cleaned and painted when necessary. The coil mounting bolts should be checked and tightened and any evidence of vibration noted.

Maintenance data - Air handling units and fan coil units

Electric motors

The only component in frictional contract are the bearings.

Bearings are supplied lubrication sealed for life and bearing life is governed by a number of factors, namely operation ambient temperature and motor size.

The following are recommended hours of operation between re-greased or replaced bearings:

Ambient
Up to 3kw
4.0-7.5kw
11.0-30.0kw
0°-25°C
36,000
30,000
20,000
25°-40°C
18,000
15,000
10,000

Any sign of overheating or arching should be investigated without delay, as should excessive increase of dirt or moisture.

Fan shaft bearing

Bearings are supplied lubricated sealed for life, with the exception of those mounted on cast iron supports, and ore equipped with the grease point.

Periodic cleaning out and renewal of grease is necessary. Apply grease while bearings are running, adding slowly until a slight bleeding of grease from the seal is noted. Care should be taken not to over-lubricate.

Apply re-greasing as indicated above for electric motor bearings.

Belts and pulleys

Vee belts must be correctly tensioned at installation and then re-tensioned after approximately twenty-four hours of running to ensure any inherent stretching is accommodated.

Design life of approximately 25,000 hours should be expected and checked for wear every 3,000 hours of operation.

Misaligned pulleys are a major cause of vee belt wear and pulley alignment should be checked after a similar 3,000 hours operation.

Potential logistics forces and/or mishandling can lead to unit being installed outside of checked condition ex-factory. Routine checks in first hours of operation/commissioning must include;

  1. All guarding is in place and clear of moving parts.
  2. Belt tension where applicable is adjusted to within acceptable limits.
  3. Bolt tension/torque on critical moving parts is checked. 

Coils

The primary maintenance consideration for finned air heating and cooling coils are cleanliness of heat transfer surface and freedom from corrosion and leakage.

In the best of filtered systems, coil fins and tubes can become clogged with dust, fluff, lint etcetera, which may become the source of external corrosion in addition to reducing heat transfer efficiency.

The frequency of cleaning will depend upon the cleanliness of the air flowing through the coil. If used for heating or cooling outdoor air with intake close to street level in areas with a high degree of air pollution, more frequent in sections will be required than would be where the intake is high and air pollution light.

Filters

Filters are dry media washable and should be cleaned as follows:

  1. Remove surface lint and loose dirt with vacuum cleaner attachment or by gently rapping over a newspaper.
  2. Flush water though inlet (dirty) side of filter. In severe cases, immersion and agitation in cold water and mild detergent may be necessary. Rinse thoroughly and dry.

If filters are of a different type, follow filter manufacturer's instructions.